For those collectors out there. I have a copy of Viogression's Passage in Tombstone Records/Progressive International from 1992, however my matrix number has an IFPI code: THE PASSAGE X6829T IFPI L531

Didnt the IFPI codes started to be used in 1994? I will appreciate if any one can confirm if this matrix number is the correct one?

audacity > analyze > plot spectrum
also on the left there's little arrow, click it and you get some view options, eg spectrogram
excellent work so far

It would be interesting if you had an original copy with this same track for comparison.

wav file ripped directly from my shitty arse vengeance rising cd bootleg, whoever made the thing used mp3s or some other such lossy format
notice how the frequencies above 20 k aren't there?

and this dark angel leave scars vinyl rip

...
farkin heinous!

Not a fair comparison, the CD format only has frequencies up to 22 kHz while vinyl can go up to 45 kHz. Both are good as freqs > 22 kHz aren't heard unless you're, for instance, a dog, or a cat (well, even vinyl is lacking for cats as they can
cat detect sound all the way up to 64 kHz, and they are pretty damn cute on top of that).

Actually, CD audio has a sampling rate of 16bit/44Khz, what vinyl has better is a wider dynamic range.

Also there's another factor that is the actual bit rate of the MP3 to CD audio conversion, since MP3 has a sampling rate identical to an audio CD. What happens, and is partially explained in that linked article, is that at lower bit rates the codec that compresses the file cuts all frequencies above a certain threshold to save physical space. MP3 at 320Kbps is capable of reproducing the audio perfectly, although the fact that it's a lossy format will make some things be lost as well, although those are the ones which can only be "felt" or heard with really high-end gear,

It would be interesting if you had an original copy with this same track for comparison

That's the sampling rate, the Nyquist frequency is half that: 22 kHz.

the only results that looked a lot different were the vinyl rips

I tried reading the Wiki article about the Nyquist frequency but it's like reading Chinese!

So in real life all actual audio is only reproduced within the borders of the Nyquist frequency, i.e. half of the original sampling rate? And is that why the graph only shows a curve up until the upper 20Khz?

my first question is: did you rip the cd to wav or mp3?

It would be much easier to have one original copy of each rare CD and make a lossless copy of it, then you can reproduce the entire audio tracks seamlessly. No one would be able to tell the difference. And yes, according to the graphs and articles linked before you can tell if the source files were low bit rate MP3 files because of the cut-off threshold. Now if the copy is made from high bit rate MP3 or lossless files it's nearly impossible to discern I guess.

If you use lossless you shouldn't be able to discern as they're bit equal to the wav/cdda. As for mp3 high bit rates tend to get pretty close but that depends on the encoder, you should be able to find something fishy most of the time.

Actually that works for tracks but to make an exact CD copy you need a bit more than each of the CD tracks in lossless (you'll need the pre-track gap data, for instance).

Those graphs above are very interesting indeed. It would be interesting to use that program to see if older albums which are lesser compressed than more recent ones have differences above the 20Khz mark. Basically to see if loudness war actively killed everything above 20Khz on modern productions.

I don't think so, if anything, the color intensity would be brighter across the whole frenquency range, up to 22 Khz.

That should never happen, most things happen on the bass, mid and high ranges, little more than cymbals and hit-hats go on the higher frequencies. So the graphic should always be brighter on the bass/mid/high. Check http://obiaudio.com/2010/07/11/eq-chart/

Yes, but since the loudness of the whole signal is being boosted, the higher frequencies will also be louder, resulting in a brighter color in a spectrogram.
Relative to lower frequencies, of course, they will always be less intense.
What i wanted to say, though, is that i think it's unlikely that modern Loudness War productions would remove any content above 20 KHz.

speaking of loudness wars etc [brief thread derailment by the way do we have a thread related to this sort of stuff?]

iron maiden - somewhere in time - 01 - caught somewhere in time
both files ripped to wav from cd using the same method
top = remaster
bottom = original

so if i'm reading this correctly there appears to be no way to tell if a cd has been burned from mp3 files or wav files or flac or indeed even mastered [made from the original master, i'm unsure of the actual terminology]
because they all appear to look very similar
the only way it'll look any different is if it was ripped from vinyl or burned from really crappy files, right?

that's burst my bubble a wee bit, i was hoping there was a way to tell

so if i wanted to make some bootleg cds all i'd have to do rip the vinyl, burn those files to the cd and claim they have "much higher bitrates than mp3s [or some other such nonsense] hence they have to be legit"
i bet the scumbag bootleggers already know about this

Just out of curiosity, in what bit rate did you rip the CD? Around 70-80Kbps?

320kbps with the AAC format.

Anyone has the Omen - Battle Cry reissue from Metal Blade with the black backcover with the large Omen Battle Cry?


Matrix is 14215-2 03 with a DiscUSA logo
SID codes: IFPI L794 IFPI 2D40.

Anyone with a similar edition? I guess I should discard this as a counterfeit and bug the seller, if not for anything else because of packaging + torn spine.

If you post a photo I can compare it with other DiscUSA matrix that I have.
I don't think that logo could be easily faked...